Safety appliance for hydraulic accumulators



Aug. 7, 1928.

M. MACK SAFETY APPLIANCE FOR HYDRAULIC ACCUMULATORS Filed oct. 2v, 1925 UNITED STATES P MARTIN MACK, F CANNSTATT-STUTT MISCH- UND KNETMASCHINEN RIK, WERNER & PFLEIDERER,

FABRIK, CANNSTATTER OF CANNSTATT-STUTTGART, GERMANY.

,i y 1,679,433 ATENT oFFicE.

GART, GERMANY, ASSIGNOR TO CANNSTATTER DAMPF-BACKOFEN-FAB- SAFETY APPLANCE FOR HYDRAULIC ACCUMULATORS.

Application filed October 27, 1925,

My invention refers to for hydraulic accumulators ni safety appliance to the kind in which the weight customarily employed in these devices is replaced by coinpressed air, a freely movable piston act-:ng

as a partition between the unoer pressure. By forcing front end of the cylinder air and the liquid liquid into the in which the piston is reciprocating the piston is moved to the rear and compresses the air iii the rear end of the cylinder. The energy stored at this end is available liquid under pressure n been cut off and the liquid after the delivery of to the front end has space at the front end of the cylinder has been connected to the stem.

It is an object of my invention to provide a safety appliance which automatically empties the water-filled part of the cylinder when the piston oversteps a certain limit on its inwar To this end I provide in of the cylinder, at the air end, a the piston when the predetermined limit, the water in the water end d stroke. the air-filled partand preferably in its head Valve which is operated by piston oversteps the thereby discharging of the cylinder so that the piston does not move further, and damage to the piston or the cylinder head by collision of these parts In the drawings afIiXed tion and forming tor equipped with a safety is prevented. to this specificapart thereof an aecumulaappliance according to my invention is illustrated diagraminatically by way drawings of example.

In the Fig. 1 is an axial section, Fig. 2 is a partial plan view,

, Fig.

3 is an elevation, partly in section, of

the front end of the cylinder on a larger scale.

Referring to the drawings, 1 is the working cylinder and 2 is the piston capable of free reciprocation within said cylinder.

This piston is freely mounted on a governing rod 3 arranged axially in the cylinder,

the piston being as to prevent the packed against the rod so passage of compressed air or liquid. On the rod is mounted near the front cylinder head 6 Piston 2 is free to slide on the rod 3 between the two checks. The rod the cylinder head 6 and on is mounted a cross head 3 extends across its free end there 8 slidable on a ore especially Serial No. 65,170, and in Germany August 4, 1925.

slide bar 7 mounted in the cylinder head (5 and carrying on its free end a rod 9 carrying two laterally staggered cams 1() and 1l adapted to cooperate with rollers 12 and 13 mounted on the ends of a twee-armed lever 14 which is keyed onto a shaft l5 mounted in a forked bearing 1G. On the shaft 15 is further mounted the two-arnied lever 17, to the end of which are pivoted the push rods 18 and 19 governing valves 20 and 21 which regulate the deliver 7 of liquid to the front end of the cylinder from a pump indicated diagrammatieally at 44 and operated by any suitable means, not shown, through the delivery valve chest 45, a pipe 46 and a passage 46 in the cylinder cover 6. The front end of the passage 46 is connected with the system, not shown, by a pipe 47.

As will appear from F ig. 3 the chamber of the valve 21 is connected with a cylinder 2 by a passage 36 in the cylinder head 6 and with a chamber of the valve by a passage 38 and the latter valve chamber, in turn, is eonnected with atmosphere by a passage 37 and a pipe 37. 38 is a passage connecting the passage 38 with a cylinder 39 in which a piston 40 is free to reciprocate against the pressure of a spring 41. 42 is a cam at the end of the piston rod, and 43 is the suction valve of the pump 44. It will appear that when liquid under pressure enters the cylinder 39 the cam 42 will lift the suction valvc 43 so that the pump 44 becomes inoperative.

instead of this cut-out device, a by-pass or any other suitable means, not shown, might be provided for interrupting the delivery of liquid to the pump.

The cylinder head 40 on the rear end of cylinder 1 is provided with means for distributing the compressed air. The cylinder head 40, while lacking the change-over valve customarily combined with these accumulators is provided with a safety device preventing the admissible pressure from being overstepped when the piston approaches the cylinder head. It is further provided with means for emptying the cylinder.

The admission of air is provided for by a channel 22 in the cylinder head 40, which opens into the atmosphere. The check valve 23 iiuerted in this channel serves for admit ting atmospheric air into the cylinder whenever tlie accumulator is not in operation. so that the piston 2 is free to return io its initial position at the front end of the cylinder. To a conduit 24 are connected steel tanks or other reservoirs (not shown) for increasing the air space ol' the accumulator. The conduit 24 as well as that part ot' the channel which is governed by the check valve 23 communicate through channel with the interior otl the cylinder.

A push rod 27 movable in an axial boring of the cylinder head 40 and extending into the cylinder is adapted to cooperate with a valve 30 acted upon by a spring 29 and serving to control the connection ot' a pipe 3i which is in communication with the liquid space of the cylinder through a passage 31 in the front cylinder head 6 with a discharge passage 32 in the cylinder head 48.

A spindle 33 mountel on valve 3() and which is secured against rotation by a spline or the like has mounted on its threaded end a nut carrying a handle 34 by means of which the valve 30 can be manually lifted oit its seat against the action of spring 29 in order to empty the liquid-tilled space et the cylinder by way ot pipe 31 and discharge passage 32.

This accumulator operates as follows2 As long as its working cylinder by the pump 44 is empty, the piston 2 abuts against the cylinder head 6. As soon as water is vforced into the cylinder, the piston 2 will glide along rod 3 until it reaches the rear check whereby rod 3 is drawn into the cylinder carrying along with it rod 9. As cam mounted on this latter rod passes underneath roller 12, this latter is lifted thereby rotating lever 14. Lever 17 being forced to follow the rotation of the shaft depresses the push rod 19 of the valve 20 and raises the push rod 18 of the valve 21. In consequence, valve 2() closes the passage 37 and valve 21 connects the passages 3G and 38 so that liquid from the cylinder 2 enters the cylinder 39 and causes the suction valve 43 of the pump 44 to be raised so that the pump is rendered inoperative and the supply of liquid to the front end of the cylinder 1 ceases.

It owing to any irregularity in the control of the piston this latter should move beyond its normal end position` check 5 will litt spindle 27, thereby opening valve 3() which will cause liquid from the accumulator cylinder to flow back through pipe 31 and channel 32. This relieves the pressure in the Water space in front of the piston 2 so that the piston ceases to move. It desired a connection. not shown, may be provided by which the liquid from 32 is returned to the pump. In consequence thereof the piston can never come in contact with the cylinder head 40, so that all undue pressure is obviated.

when the piston 2 moves in the opposite direction, the governing rod 3 being influenced by the pressure prevailing in the cylinder will follow its movement as Var as the position of check 4 on -this rod will permit it. Then this check meets the cylinder head (3, the rod 3 is arrested but the piston 2 will continue its movement, gliding on the rod Cam 11 on rod 9 is carried in time below roller 13 so to rotate lever 14, push rod 18 will be lowered while push rod 19 is raised, whereby the accumulator is cut oit from the pump control cylinder vaive 21 closing the passage opening the connection between the passage 33 and 3T, allowing the liquid from 39 to be discharged so that the spring 4 is tree to return the piston 40 to its initial position and the pump 44 is set operating again.

The accumulator has been shown in horizontal position. It may be arranged in vertical position it desired but since this accuni lfuan' is ot the pneumatic and not of the gravity type7 it is not limited to vertical arrangement. Horizontal arrangement has the advantage o1 being more convenient because generally more space is available in a building in horizontal than in vertical direction so that it is possible to arrange a horiz/.ontal accumulator without breaking through a wall, or several walls, oi the building whereas with the accumulator in vertical position it will be inevitable to break through one iloor or several floors of the building and the valve gear at the top of the accumulator is generally in a position which renders access thereto difficult. so that the gear and the mechanisms connected with the gear are liable to be neglected. With the accumulator arranged in horizontal position. on the other hand. there is n0 diiticulty about getting at the valve gear and its mechanism for inspection and lubrication.

I wish it to be understood that I do not desire to he limited to the exact details of construction shown and described for obvious modiications will occur to a person skilled in the art.

I ciaim:-

1. A safety appliance for hydraulic accumulators comprising a cylinder, a piston axially movable in said cylinder, means for supplying said cylinder with water on one and with compressed air on the other side of said pistou, means ior emptying the water-illed part ot lsaid cylinder and means on the airtillcd side of said cylinder adapted to be influenced b v said piston for operating said emptying means.

2. A safety appliance for hydraulic accumulators comprising a cylinder, a piston axially movable in said cylinder, means for supplying said cylinder with water on one and with compressed air on the other side of said piston, means for emptying the water-filled part of said cylinder, means on the air-filled 36 and the valve 39 by the A side of said cylinder adapted to be influenced by said piston and separate manually operable means for operating said emptying means.

3. A safety appliance for hydraulic accu mulators comprising a cylinder, a piston aXially Inovable in said cylinder, means for supplying said cylinder with Water on one and with compressed air on the other side of said piston, means for emptying the Waterfilled part of said cylinder and a valve on the air-filled side of said cylinder adapted to be influenced by said piston for operating said emptying means.

4. A safety appliance for hydraulic accumulators comprising a cylinder, a piston axially movable in said cylinder, means for supplying said cylinder with Water on one and with compressed air on the other side of said piston, means for emptying the Water-filled part oi said cylinder, a valve on the air-filled side of said cylinder adapted to be influenced by said piston for operating said emptying means and separate means for actuating said valve by hand.

5. A safety appliance for hydraulic accumulators comprising a cylinder, a piston axially movable in said cylinder, a rod eX- tending into said cylinder and arranged to be displaced by said piston, means for supplying said cylinder on one side of said piston with Water, means connected With said rod for controlling said Water supplying means, means for supplying said cylinder With compressed air on the other side of said piston, means for emptying the Water-filled side of said cylinder and means on the airilled side of said cylinder adapted to be influenced by said piston for operating said emptying means.

6. A safety appliance for hydraulic accumulators comprising a cylinder, a piston axially movable in said cylinder, means for supplying said cylinderl with Water on one end and with compressed air on the other end, two checks on said rod opposite either face of said piston and adapted to be engaged thereby, said rod projecting from the Water-lled part of said cylinder, valve gear operatively connected with said Water supplying and emptying means, and cam means operatively connected with the projecting end of said rod for controlling said valve gear.

In testimony whereof I atliX my signature.

MARTIN MACK. 

